Thank you, thank you, thank you!
I did what you suggested (brilliant!) and went to install it and the KF stated that there was a conflict with an already installed program. So I hunted around - no more app icons on the carousel or in Favorites - but by pressing on the Apps menu - they were all there! Even the Amazon free apps (I didn't have any paid apps).
So now I can give it back as a useable device. The 13-yr-old girl isn't much into tech nor are the parents - so this is a real windfall for them. Finances are so difficult here in Greece now that I am thrilled to help them make better use of their gift.
May be un-cool to say, but I really like dealing with Amazon (products). Not perfect, but surprisingly very good.
Blossom, I was actually thinking of PM'ing you with this question as you usually have excellent advice and suggestions! You beat me to it. I really appreciate the help.